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Monday, May 2, 2011

It is hard enough to brew a great sour ale when you know what microbes you are pitching, so why did I want to take on the additional challenge of souring a beer with unknown local microflora? I think it was some combination of the romance and curiosity of brewing a beer that gets its unique character from the area it is brewed (terroir). Some people suggest trying a smaller test batch first, but if I have to wait more than a year to see how the evaluation goes I might as well have five gallons to show for it.

Propagating the wild yeast I captured in my backyard and barrel room boosted my confidence, the starters had a surprisingly clean flavor with a hint of lactic tartness. Judging souring microbes after a few weeks can be dangerous since there are strains that may not have made their presence known by this point; I'll be interested to see how the flavor develops as the beer slowly ferments.

The brew day was very similar to the one for my third Lambic (lots of details/pictures on the process in that post). I applied what I had learned from that batch to the turbid mash I did for this beer. Despite the complexity and extra attention required (it helped that a few friends stopped by) a turbid mash only takes about 2 hours (it is the long boil to reduce all of that wort that kills most of your day). I adjusted my efficiency down from my previous attempt to hit my target OG (despite the long boil and scalding sparge my efficiency was similar to my standard brewing process). The only change I made to the mash schedule was to hold the turbid portion of the runnings at 190 F (instead of 176 F) to ensure that it would raise the mash to 170 F when it was added to reach mash-out.

With 8.5 gallons of wort collected I started the 225 minute boil. I added three ounces cheesy 2007 Willamettes near the start (a generous addition of aged hops is helpful for a beer like this to slow the growth of spoilage microbes). When I tasted the wort I was surprised how little bitterness the hops imparted (although looking at them I shouldn't be too surprised), luckily none of their funky aromas carried over either.

After force chilling the wort I pitched about one quart from each of the two starter. While there was some yeast(?) that had flocculated to the bottom of the starter vessels I did not want to decant them because there were most likely numerous organisms that had not dropped out. Visible fermentation took about 24 hours to commence. During the first week I held the ambient temperature at 65 F to give the yeast the best chance to complete a healthy/calm primary fermentation, letting it rise slightly after that. The krausen was primarily composed of large, delicate bubbles (a sign that the strains at work are probably less flocculant than standard brewer's yeasts).

My plan is to leave this beer in the primary fermenter for the next 12-18 months. At that point, assuming it doesn't taste terrible, I'll bottle half of it as is and add a few pounds of (extremely bland) mulberries from the tree in my backyard to the remainder. If this batch is successful I may use it to start next year's Lambic, heading down the road to a truly wild house culture.

Notes
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3/24/11 Started spontaneous fermentation starters. 1.030, .5 oz aged hops, and 1/4 tsp nutrient: upstairs, backyard, and in the barrel room. Did not force chill, and put them in pots covered with cheesecloth. The next morning I moved them all inside and put them in growlers with airlocks.

Minor activity after a few days.

3 weeks later I tossed the upstairs (black mold) and stepped up the other two.

The outside had the best aroma and most active/flocculant yeast. The barrel room smelled a bit off, but seemed to be Brett (pellicle?).

Brewed 4/23/11 With Jaime, John, Brian B, and Martin

Wheat was whole/unmalted from the COOP, Pils was Best Malz.

Held the turbid portion @190 F before adding it back for the mash out.

Collected ~8.5 gallons of 1.032 runnings. Added 1 qrt of water with 30 min left in the boil since I was lower on volume than expected.

It is a better bottle, they are pretty much all I use for aging sours. I’ve never had an issue with acetic acid formation or oxidation using them for sour beers. I talked to their tech guy a few years ago, and he said the oxygen permeability is minimal (lower than the numbers cited in Wild Brews for PETG, which were 1/6 of a bucket).

I also like being able to see the beer without the breakage risks that glass poses.

Lambics are traditionally left in a single vessel to ferment/age. As the Saccharomyces breaks down it releases nutrients that allow the Brett to continue working. It leads to a more rustic character, but up to 18 months I’ve never had any autolysis issues (never gone past that).

Do you think that autolysis can be a problem with a solera? I ask because we are attempting a Flanders Red solera. We did primary fermentation with ale yeast in carboys and then racked to the 55 gallon barrel where we added the Wyeast Roselare starter. If we never completely drain the barrel, are we in trouble?

You may have an issue with the solera down the road. I know Will at CBC said in an article that after a few years he had to drain his barrels and clean them out because he started to taste autolysis byproducts. I’m not sure how we are going to deal with our solera barrels when that time comes.

Truly amazing post. Great info as always, but even more inspiring than usual thanks to the more gutsy move of tackling a spontaneous fermentation. Cheers to you! Here's hoping that you do indeed establish a house lambic culture, and that many others follow suit. I for one really do think you ought to write a book oriented towards homebrewers and the new frontiers of American wild brewing practice. Still seems to me that the biggest challenge for barrel-less homebrewers is figuring out how to allow for the right levels of micro-oxygenation or whatever, and the porous surface material that encourages microbes to survive over the course of multiple batches. Anyway, just wanted to chime in that your blog is very inspirational, and keep up the good work!

I think moving oak cubes from batch to batch is probably the best option for homebrewers to mimic the bug retaining properties of a barrel. I’ve had pretty good luck without worrying too much about micro-oxygenation (the oak chair leg trick never did much for me), but there is a certain character (and depth of sourness) you get from a barrel that I haven’t been able to get from my other fermenters.

The info. from this and your previous 4 attempts at a Local Lambic are great. I'm getting ready to try my first in June when Los Angeles has pretty cool whether. Thanks for tons of tips...I'll be following your progress too!

Mike - I'm gearing up to brew a batch with my own locally caught yeast. Just curious if you kept any of your yeast for future batches or if you pitched all of it into this batch. And if you saved any of it, how?

I did save some of my two starters, although at the moment they are still sitting in the same jugs. I’ll probably just end up tossing it out and using some of the batch to pass on the microbes if it turns out to be an experiment worth repeating. If you want to save them I would keep them cold and feed them every 4-6 weeks with some fresh yeast (it is hard to keep mixed cultures going without one microbe taking over).

It is coming along nicely. The acidity is still relatively low, but the Brett character is getting there. The tropical fruit it had when it was young as been replaced by fresh pipe tobacco, and some classic earthy Brett funk. I’m planning to bottle half of it in a month or two, and put the rest onto a few pounds of mulberries (just waiting for the fruit on my tree to ripen).

It is actually traditional to age a lambic in the primary fermentor (usually a barrel) until it is ready to blend or transfer onto fruit. As the Saccharomyces dies it releases sugars, nutrients, and fatty acids that the Brettanomyces uses to continue its fermentation. I find this results in a more rustic/complex character that you do not get when racking a sour after primary fermentation is complete. Not saying one or the other is better, just another tool you can use to create the character you want.